Allow comments in extension config files.

chrome/common/extensions/api/experimental.fonts.json

+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
 [
   {
     "namespace": "experimental.fontSettings",
     "functions": [
       {
         "name": "getFontName",
         "type": "function",
         "description": "Gets the font name of the current setting for a given script and font family.",
         "parameters": [
           {
@@ skipping 62 matching lines @@
             "type": "function",
             "name": "callback",
             "optional": "true",
             "parameters": []
           }
         ]
       }
     ]
   }
 ]